12 A TEXT-BOOK OF GRASSES 
ALCOHOL 
11. Another important product of the grains is alco- 
hol—For this purpose the starch is first converted by 
means of diastase into maltose, a kind of sugar, and the 
sugar is fermented by means of a yeast plant. The fer- 
mented liquor is distilled, the product being alcohol. The 
diastase is an unorganized ferment present in the germi- 
nating grains. This converts the stored starch of the 
seed into a soluble form, a sugar, which can be absorbed 
by the young plant. The grain to be used as a source of 
alcohol is allowed to germinate, is heated to kill the 
embryos, and is then fermented with yeast. This con- 
verts the sugar into alcohol and carbon dioxide. If beer is 
the product desired, barley is the grain usually employed 
and the process is stopped at this point. If a distilled 
liquor is desired, the material is distilled. The details of 
the manufacture of the various alcoholic products belong 
to the study of industrial chemistry. Wine is produced by 
fermentation from the juices of fruits containing sugar, 
especially the juice of the grape. This liquid, when dis- 
tilled, produces a brandy. 
MISCELLANEOUS USES OF THE GRAINS 
12. In the manufacture of starch or alcohol, the grains 
furnish many other substances, often as by-products. 
Among these may be mentioned gluten meal and corn 
oil, the one from the protein and the other from the fat 
of the seed. Corn oil is expressed from the grain before 
the starch is extracted, or it is obtained from the residue 
in the fermentation vats in the manufacture of alcohol. 
Much of the commercial vinegar is produced from malt 
